CN111751985A - Optical scanners, 3D measuring devices and robotic systems - Google Patents

Abstract

The present invention provides an optical scanner, a three-dimensional measuring device, and a robot system equipped with the three-dimensional measuring device. The optical scanner is characterized by comprising: a reflecting mirror having a reflecting surface for reflecting light and a first back surface located on the opposite side of the reflecting surface; a permanent magnet arranged on the first back surface of the reflecting mirror; a support portion , which supports the mirror and has a second back on the same side as the first back; a shaft part connects the mirror with the support so that the mirror can swing around the swing axis; the first a member arranged on the second back surface of the support portion; a second member, which is orthogonal to the swing axis and supports the first member in a cantilever direction along the second back surface; and a third member, The second member is arranged opposite to the first member and is connected to the second member, and the electromagnetic coil is arranged between the first member and the third member.

Description

Optical scanners, 3D measuring devices and robotic systems

technical field

The invention relates to an optical scanner, a three-dimensional measuring device and a robot system.

Background technique

Patent Document 1 discloses an optical scanning device that deflects incident light to perform optical scanning. The optical scanning device described in Patent Document 1 includes: a rectangular plate-shaped mirror member formed with a mirror surface; a frame member supporting the mirror member via a pair of torsion bars; and a permanent magnet bonded to the opposite side of the mirror surface of the mirror member side surface. In addition, Patent Document 1 discloses that the frame member is held between the upper cover and the lower cover, and the mirror member and the permanent magnet are sealed in the storage space. Furthermore, the optical scanning device includes an electromagnet including a yoke provided in the vicinity of the permanent magnet and a coil wound around the yoke. Furthermore, Patent Document 1 discloses that the torsion bar is twisted as a rotation axis by the interaction of the magnetic field generated in the vicinity of the gap of the yoke and the permanent magnet, and the mirror member is reciprocated. In addition, the lower cover is located between the electromagnet and the permanent magnet, and it is difficult to reduce the gap between the electromagnet and the permanent magnet, so in order to increase the Lorentz force acting on the permanent magnet, it is necessary to increase the amount of flow through the electromagnet. current.

Patent Document 1: Japanese Patent Laid-Open No. 2009-69676

SUMMARY OF THE INVENTION

However, in the optical scanning device described in Patent Document 1, when the current flowing through the electromagnet increases, the amount of heat generated by the electromagnet increases, and thermal stress is generated in the frame member, which causes deformation of the frame member. As a result, there is a problem that the accuracy of the direction of the mirror-deflected light is lowered.

The optical scanner of the present invention is characterized by comprising: a reflecting mirror having a reflecting surface for reflecting light and a first back surface located on the opposite side of the reflecting surface; and a permanent magnet arranged on the first back surface of the reflecting mirror a support part, supporting the reflector, and having a second back surface located on the same side as the first back surface; a shaft part, connecting the reflector with the support part, so that the reflector can swing around the swing axis a first member, disposed on the second back surface of the support portion; a second member, orthogonal to the swing axis, cantilevered to support the first member in a direction along the second back surface; A third member is arranged opposite to the first member via the second member and is connected to the second member; and an electromagnetic coil is arranged between the first member and the third member.

Description of drawings

FIG. 1 is a diagram showing the overall configuration of a robot system according to the first embodiment.

FIG. 2 is a diagram showing the overall configuration of a three-dimensional measurement device included in the robot system shown in FIG. 1 .

FIG. 3 is a perspective view showing the three-dimensional measuring apparatus shown in FIG. 2 .

FIG. 4 is a perspective view showing the inside of the three-dimensional measuring apparatus shown in FIG. 3 .

FIG. 5 is a plan view showing an example of pattern light projected by the projection unit shown in FIG. 4 .

FIG. 6 is a plan view showing an optical scanning unit included in the three-dimensional measurement apparatus shown in FIG. 4 .

FIG. 7 is a cross-sectional view of the optical scanning unit shown in FIG. 6 .

FIG. 8 is a perspective view of the optical scanning unit shown in FIG. 7 .

FIG. 9 is a view showing a state in which the temperature of the optical scanning unit shown in FIG. 7 rises and thermal stress is generated to cause warpage of the first member.

FIG. 10 is a diagram showing a state in which the temperature of the optical scanning unit shown in FIG. 7 rises and thermal stress is generated to cause warpage of the first member.

11 is a cross-sectional view showing an optical scanning unit as an optical scanner according to a second embodiment.

Description of reference numerals

1: Robot system; 2: Robot; 4: 3D measuring device; 5: Robot control device; 6: Main computer; 21: Base; 22: Robot arm; 24: End effector; 40: Housing; 41: Projection part; 42: laser light source; 44: optical system; 45: optical scanning part; 45A: optical scanning part; 47: imaging part; 48: control part; 49: measuring part; 221: first arm; 222: second arm ;223:third arm;224:fourth arm;225:fifth arm;226:sixth arm;251:first drive;252:second drive;253:third drive;254:fourth 255: fifth drive; 256: sixth drive; 401: bottom; 402: top; 403: front; 403a: window; 404: back; 405: side; 406: side; 441: 442: Rod lens; 450: Reflective surface; 451: Reflector; 451a: Back surface; 452: Support part; 452a: Back surface; 453: Shaft part; 455: Permanent magnet; parts; 458: second part; 459: third part; 471: camera; 472: photographing element; 473: condenser lens; 4562: winding; 4564: first core; 4566: second core; 4571: opening ;4572: Support surface; 4592: Support surface; J: Swing axis; L: Laser beam; O: Center; O1: First axis; O2: Second axis; O3: Third axis; O4: Fourth axis; O5 : Fifth axis; O6: Sixth axis; P0: Reference plane; P1: Plane; PL: Pattern light; W: Object; θ: Angle.

Detailed ways

Hereinafter, the optical scanner, the three-dimensional measurement device, and the robot system of the present invention will be described in detail based on the embodiments shown in the drawings.

first embodiment

FIG. 1 is a diagram showing the overall configuration of a robot system according to the first embodiment. FIG. 2 is a diagram showing the overall configuration of a three-dimensional measurement device included in the robot system shown in FIG. 1 . FIG. 3 is a perspective view showing the three-dimensional measuring apparatus shown in FIG. 2 . FIG. 4 is a perspective view showing the inside of the three-dimensional measuring apparatus shown in FIG. 3 . FIG. 5 is a plan view showing an example of pattern light projected by the projection unit shown in FIG. 4 . FIG. 6 is a plan view showing an optical scanning unit included in the three-dimensional measurement apparatus shown in FIG. 4 .

The robot system 1 shown in FIG. 1 includes: a robot 2; a three-dimensional measuring device 4, which uses a laser beam L to perform three-dimensional measurement of an object W; a robot control device 5, which controls the driving of the robot 2 based on the measurement results of the three-dimensional measuring device 4; And the host computer 6 can communicate with the robot controller 5 . In addition, these various parts can communicate by wire or wirelessly, and can also communicate through a network such as the Internet.

1. Robots

The robot 2 is, for example, a robot that performs operations such as material supply, material removal, conveyance, and assembly of precision instruments or components constituting the precision instruments. However, the use of the robot 2 is not particularly limited. The robot 2 according to the present embodiment is a six-axis robot, and as shown in FIG. 1 , has a base 21 fixed to the floor or ceiling, and a robot arm 22 connected to the base 21 .

The robotic arm 22 has: a first arm 221, which is rotatably connected to the base 21 around a first axis O1; a second arm 222, which is rotatably connected to the first arm 221 around a second axis O2; a third arm 223 , is rotatably connected to the second arm 222 around the third axis O3; the fourth arm 224 is rotatably connected to the third arm 223 around the fourth axis O4; the fifth arm 225 is rotatable around the fifth axis O5 The fourth arm 224 is freely connected to the sixth arm 226, and the fifth arm 225 is rotatably connected to the sixth arm 226 around the sixth axis O6. In addition, an end effector 24 is mounted on the sixth arm 226 for the robot 2 to perform work. In addition, the end effector 24 side of the first arm 221 to the sixth arm 226 is also referred to as a "front end" or "front end side", and the base 21 side is also referred to as a "basal end" or "basal end side".

In addition, the robot 2 has: a first driving device 251 to rotate the first arm 221 relative to the base 21; a second driving device 252 to rotate the second arm 222 relative to the first arm 221; and a third driving device 253 to rotate The third arm 223 rotates relative to the second arm 222; the fourth driving device 254 rotates the fourth arm 224 relative to the third arm 223; the fifth driving device 255 rotates the fifth arm 225 relative to the fourth arm 224; and the sixth driving device 256 to rotate the sixth arm 226 relative to the fifth arm 225 . Each of the first driving device 251 to the sixth driving device 256 includes, for example, a motor as a driving source, a controller for controlling driving of the motor, and an encoder for detecting the amount of rotation of the motor. In addition, the first drive device 251 to the sixth drive device 256 are independently controlled by the robot control device 5 .

In addition, the robot 2 is not limited to the structure of this embodiment, For example, the number of arms included in the robot arm 22 may be 1 to 5, or 7 or more. In addition, for example, the type of the robot 2 may be a SCARA robot or a dual-arm robot having two robot arms 22 .

2. Robot control device

The robot control device 5 receives the position command of the robot 2 from the host computer 6, and independently controls the first drive device 251 to the sixth drive device so that the first arm 221 to the sixth arm 226 reach the position corresponding to the received position command. 256 drive. The robot controller 5 is constituted by, for example, a computer, and includes a processor (CPU) that processes information, a memory communicably connected to the processor, and an external interface. Various programs executable by the processor are stored in the memory, and the processor can read and execute various programs and the like stored in the memory.

3. Three-dimensional measuring device

Next, the three-dimensional measurement device 4 according to the first embodiment will be described.

The three-dimensional measurement device 4 performs three-dimensional measurement of the object W using the phase shift method. As shown in FIG. 2 , the three-dimensional measurement device 4 includes a projection unit 41 that projects pattern light PL for three-dimensional measurement formed by the laser beam L onto a region including the object W, and an imaging unit 47 that projects the pattern light PL on which the pattern light PL is projected. The area of the object W is captured to acquire image data; the control unit 48 controls the driving of the projection unit 41 and the imaging unit 47; the measurement unit 49 measures the three-dimensional shape of the object W based on the image data; and the casing 40 accommodates these various parts.

In this embodiment, as shown in FIG. 3 , the casing 40 is fixed on the fifth arm 225 of the robot 2 . In addition, the case 40 is formed in a box shape, and includes a bottom surface 401 fixed to the fifth arm 225 , a top surface 402 facing the bottom surface 401 , a front surface 403 located on the front end side of the fifth arm 225 , and a fifth arm 225 The rear surface 404 on the base end side, and a pair of side surfaces 405 and 406. Furthermore, as shown in FIG. 4 , the projection unit 41 , the imaging unit 47 , the control unit 48 , and the measurement unit 49 are accommodated in the casing 40 . However, the shape of the casing 40 is not particularly limited.

In addition, it does not specifically limit as a constituent material of the case 40, For example, various resins, various metals, and various ceramics can be used. However, from the viewpoint of heat dissipation, it is preferable to use materials having excellent thermal conductivity such as aluminum and stainless steel. In addition, the bottom surface 401 of the casing 40 may be fixed to the fifth arm 225 of the robot 2 by a joint part not shown.

The projection unit 41 is arranged in the casing 40 so as to irradiate the front end side of the fifth arm 225 with the laser beam L, and the imaging unit 47 is directed to the front end side of the fifth arm 225 to photograph an area including the irradiation range of the laser beam L It is arranged in the casing 40 . Further, as shown in FIG. 3 , on the front surface 403 of the casing 40 , a window portion 403 a through which the laser beam L is emitted is provided.

In addition, the arrangement of the three-dimensional measurement device 4 is not particularly limited, and may be arranged on any one of the first arm 221 to the fourth arm 224 or the sixth arm 226 . In addition, the projection unit 41 and the imaging unit 47 may be fixed to different arms. In addition, the control part 48 and the measurement part 49 may be arrange|positioned outside the housing|casing 40, and may be included in the robot control apparatus 5 or the host computer 6, for example.

The projection unit 41 has a function of projecting the pattern light PL shown in FIG. 5 on the object W by irradiating the object W with the laser beam L. As shown in FIG. As shown in FIGS. 2 and 4 , such a projection unit 41 includes: a laser light source 42 that emits a laser beam L; an optical system 44 including a plurality of lenses through which the laser beam L passes; and an optical scanning unit 45 (optical scanner) , the laser beam L after passing through the optical system 44 is scanned toward the object W. The laser light source 42 is not particularly limited, and for example, a semiconductor laser such as a vertical cavity surface emitting laser (VCSEL) and a vertical external cavity surface emitting laser (VECSEL) can be used.

The optical system 44 includes a condenser lens 441 for condensing the laser beam L emitted by the laser light source 42 in the vicinity of the object W, and a rod lens 442 for causing the laser beam L condensed by the condenser lens 441 to be parallel to the swing axis J, which will be described later. That is, the depth direction of the drawing of FIG. 2 extends linearly.

The optical scanning unit 45 has a function of scanning the laser beam L formed in a linear shape by the rod lens 442 . The optical scanning unit 45 is not particularly limited, and for example, a MEMS (Micro Electro Mechanical Systems, micro-electromechanical system), a galvanometer mirror, a polygon mirror, or the like can be used.

The optical scanning unit 45 according to the present embodiment is formed of MEMS. As shown in FIG. 6 , the optical scanning unit 45 includes: a mirror 451 having a reflective surface 450; a permanent magnet 455 arranged on the mirror 451; a support part 452 for supporting the mirror 451; Shaft portion 453 ; first member 457 arranged on support portion 452 ; second member 458 connected to first member 457 ; third member 459 connected to second member 458 ; .

In addition, in FIG. 6 , in the extending direction of the normal line of the reflection surface 450 in the stationary state, the drawing near side is the +Z axis direction, and the drawing back side is the −Z axis direction. In addition, the extending direction of the shaft portion 453 is the X-axis direction orthogonal to the Z-axis direction. In addition, let the direction orthogonal to both the Z-axis direction and the X-axis direction be the Y-axis direction.

In such an optical scanning unit 45 , the swing axis J matches the extending direction of the linear laser beam L, that is, the expanding direction of the laser beam L expanded by the rod lens 442 . Then, when a drive signal is applied to the electromagnetic coil 456, the mirror 451 swings around the swing axis J alternately forward and reverse at a predetermined cycle, thereby scanning the linear laser beam L into a planar shape. In addition, the optical scanning section 45 will be described in detail below.

The projection unit 41 has been described above, but its configuration is not particularly limited as long as it can project the predetermined pattern light PL on the object W. As shown in FIG. For example, in the present embodiment, the optical system 44 is used to expand the laser beam L in a linear shape, but the present invention is not limited to this. For example, a MEMS or a galvanometer mirror may be used to expand the laser beam L into a linear shape. That is, the laser beam L may be scanned two-dimensionally using the two optical scanning units 45 . In addition, for example, a gimbal-type MEMS two-dimensional scanning laser beam L having two axial degrees of freedom can also be used.

The imaging unit 47 images a state in which the pattern light PL is projected on at least one object W. As shown in FIG. 2 , the imaging unit 47 includes, for example, a camera 471 including an imaging element 472 such as a CMOS image sensor and a CCD image sensor, and a condenser lens 473 . The camera 471 is connected to the measurement unit 49 and transmits image data to the measurement unit 49 .

The control section 48 controls the driving of the optical scanning section 45 by applying the driving signal to the electromagnetic coil 456 , and controls the driving of the laser light source 42 by applying the driving signal to the laser light source 42 . The control unit 48 causes the laser light source 42 to emit the laser beam L in synchronization with the oscillation of the mirror 451 , for example, to project the striped pattern light PL represented by the brightness and darkness of the luminance value shown in FIG. 5 onto the object W. However, the pattern light PL is not particularly limited as long as it can be used for the phase shift law described later. In addition, the control unit 48 controls the driving of the camera 471 to capture an image of an area including the object W at a predetermined timing.

For example, the control unit 48 projects the pattern light PL on the object W four times by shifting the phase by π/2, and images the object W on which the pattern light PL is projected by the imaging unit 47 each time. However, the number of times of projection of the pattern light PL is not particularly limited, as long as it is the number of times that the phase can be calculated from the imaging result. In addition, it is also possible to perform phase unwrapping by performing the same projection and imaging using patterns with larger pitches or conversely with smaller patterns. The more types of spacing, the higher the measurement range and resolution, but the increase in the number of shots, the time required to acquire image data will increase accordingly, resulting in a decrease in the operating efficiency of the robot 2. Therefore, the number of projections of the pattern light PL may be appropriately set in consideration of the accuracy and measurement range of the three-dimensional measurement and the operation efficiency of the robot 2 .

The measurement unit 49 performs three-dimensional measurement of the object W based on the plurality of image data acquired by the imaging unit 47 . Specifically, three-dimensional information including the posture, spatial coordinates, and the like of the object W is calculated. Then, the measurement unit 49 transmits the calculated three-dimensional information of the object W to the host computer 6 .

The control unit 48 and the measurement unit 49 are constituted by, for example, a computer, and include a processor (CPU) for processing information, a memory communicably connected to the processor, and an external interface. Various programs executable by the processor are stored in the memory, and the processor can read and execute various programs and the like stored in the memory.

4. Main computer

The host computer 6 generates a position command for the robot 2 based on the three-dimensional information of the object W calculated by the measurement unit 49 , and transmits the generated position command to the robot controller 5 . The robot control device 5 independently drives the first drive device 251 to the sixth drive device 256 based on the position command received by the host computer 6 to move the first arm 221 to the sixth arm 226 to the commanded position. In addition, in this embodiment, although the host computer 6 and the measurement part 49 are mutually independent parts, it is not limited to this, and the host computer 6 may function as the measurement part 49.

5. Optical scanning section (optical scanner)

Next, the optical scanning unit 45 as the optical scanner according to the first embodiment will be described.

FIG. 7 is a cross-sectional view of the optical scanning unit shown in FIG. 6 . FIG. 8 is a perspective view of the optical scanning unit shown in FIG. 7 .

As described above, the optical scanning unit 45 shown in FIGS. 7 and 8 includes the mirror 451, the support portion 452, the shaft portion 453, the permanent magnet 455, the electromagnetic coil 456, the first member 457, the second member 458, and the third member 459. Each part is described below.

The reflection mirror 451 has a reflection surface 450 that reflects light, and a back surface 451 a (first back surface) located on the opposite side of the reflection surface 450 . The reflection surface 450 reflects the laser beam L. In addition, a reflection film (not shown) is formed on the reflection surface 450 . As the reflection film, for example, a metal film such as aluminum can be used.

A permanent magnet 455 is attached to the back surface 451 a and arranged thereon, and the permanent magnet 455 swings together with the mirror 451 . The permanent magnet 455 is magnetized in the Y-axis direction orthogonal to the swing axis J. Examples of the permanent magnets 455 include neodymium magnets, ferrite magnets, samarium cobalt magnets, alnico magnets, bonded magnets, and the like.

The shaft portion 453 connects the mirror 451 to the support portion 452 and supports the mirror 451 so as to be able to swing about the swing axis J. The optical scanning portion 45 has two shaft portions 453 and 453 extending in the X-axis direction, and the two shaft portions 453 and 453 are arranged on opposite sides of each other with the mirror 451 interposed therebetween so as to support the mirror from both sides in the X-axis direction. 451. As the mirror 451 swings around the swing axis J, the shaft portions 453 and 453 are twisted and deformed. In addition, the shape of the shaft parts 453 and 453 is not limited to the shape shown in the figure, as long as the mirror 451 can be supported so as to be able to swing about the swing axis J. For example, each of the shaft portions 453 and 453 may be constituted by a plurality of beams, or may have a bent or bent portion, a branched portion, a portion with different widths, or the like at at least one part in the extending direction.

As shown in FIG. 6 , the support portion 452 has a frame shape in a plan view from the Z-axis direction, and is arranged so as to surround the mirror 451 . In addition, the support portion 452 supports the mirror 451 so as to be able to swing by the two shaft portions 453 and 453 . In addition, the shape of the support portion 452 is not particularly limited as long as it can support the mirror 451 . For example, it may be divided into a portion supporting one shaft portion 453 and a portion supporting the other shaft portion 453 .

The first member 457 is adhesively arranged on the back surface 452a (second back surface) of the support portion 452 . The first member 457 functions as a reinforcing portion that reinforces the mechanical strength of the support portion 452 . Such a first member 457 has a plate shape extending along the XY plane. In addition, the first member 457 also has a frame shape in plan view from the Z-axis direction, and as shown in FIG. The opening 4571 secures a space for arranging the permanent magnet 455 and a space for the mirror 451 to swing.

Also, the first member 457 extends longer than the support portion 452 in the −Y axis direction. Furthermore, the end in the −Y axis direction is connected to the second member 458 . Specifically, the end in the -Y-axis direction of the surface in the -Z-axis direction of the first member 457 is a support surface 4572 supported by the second member 458 .

In addition, the second member 458 has a shape having a long axis in the Z-axis direction. The end surface in the +Z axis direction of the second member 458 is connected to the first member 457 , and the end surface in the −Z axis direction is connected to the third member 459 . Therefore, the second part 458 is interposed between the first part 457 and the third part 459 . Then, a space equal to the length of the long axis of the second member 458 is formed between the first member 457 and the third member 459 .

The third member 459 has a plate shape extending along the XY plane. Furthermore, the end in the −Y axis direction is connected to the second member 458 . Specifically, the end portion in the −Y axis direction among the surfaces in the +Z axis direction of the third member 459 is a support surface 4592 that supports the second member 458 .

An electromagnetic coil 456 is arranged between the first member 457 and the third member 459 . The electromagnetic coil 456 generates a Lorentz force by energizing an alternating current in the static magnetic field formed by the permanent magnets 455 , and swings the mirror 451 on which the permanent magnets 455 are arranged. According to such an electromagnetic driving method, since a large driving force can be generated, the swing angle of the mirror 451 can be increased while reducing the driving voltage.

In the optical scanning section 45 as described above, the second member 458 supports the first member 457 in a cantilever. For example, as shown in FIG. 7 , the cantilever support refers to a structure in which the end in the +Y-axis direction of the first member 457 is not supported as a so-called free end, and the end in the −Y-axis direction is supported by the second member 457 . 458 support. According to such a cantilever support structure, for example, even if the temperature of the first member 457 or the second member 458 rises to generate thermal stress and the first member 457 warps, the influence of warpage can be corrected.

Specifically, FIGS. 9 and 10 respectively show a state in which the temperature of the optical scanning unit 45 shown in FIG. 7 rises and thermal stress is generated to cause warpage of the first member 457 . In addition, in FIG.9 and FIG.10, illustration is simplified for convenience of description.

When the temperature of the optical scanning unit 45 rises, thermal stress occurs in the vicinity of the boundary of each of the first member 457 , the second member 458 , and the third member 459 . This thermal stress can easily manifest itself as warpage of the first part 457 . Further, as shown in FIG. 9 , in the first member 457 , the end portion where the mirror 451 is arranged is warped which is displaced in the +Z axis direction. In this way, the center O of the reflection surface 450 moves in the −Y axis direction as the warp occurs.

In addition, compared with the case where no warping occurs, the warping also causes a problem that the reflection surface 450 is tilted unplanned. Specifically, when the mirror 451 does not swing in a state where no warping occurs, the plane including the reflection surface 450 is set as the reference plane P0. When warping occurs, the shaft portions 453 and 453 are twisted and deformed, and the reflection surface 450 is unexpectedly inclined with respect to the reference plane P0. As a result, as shown in FIG. 10 , the plane P1 including the reflection surface 450 and the reference plane P0 form an inclination of the angle θ in a state where the warp has occurred.

The movement of the center O of the reflection surface 450 and the inclination of the reflection surface 450 as described above cause the center of the striped pattern light PL projected on the object W described above to be deviated from the intended position. As a result, there is a problem that the accuracy of the three-dimensional measurement is lowered.

Therefore, in the present embodiment, the second member 458 supports the first member 457 in a cantilever manner as described above. In addition, the support direction of the cantilever support, that is, the direction in which the unsupported end of the first member 457 and the end supported by the second member 458 are connected is set as the direction intersecting the swing axis J. The intersection angle may be less than 90°, which is a special case in this embodiment, the support direction is parallel to the Y-axis direction, and the swing axis J is parallel to the X-axis direction. Therefore, the support direction intersects the swing axis J at 90°.

According to this cantilever support structure, even if the first member 457 is warped as shown in FIGS. 9 and 10 , and the center of the pattern light PL is deviated accordingly, the deviating direction can be the same as that caused by the swing of the mirror 451 . The scanning directions of the pattern light PL are the same. Accordingly, even if the center of the pattern light PL is deviated, the deviation can be corrected by adjusting the swing angle of the mirror 451 . As a result, the center of the pattern light PL can be returned to a desired position, and it is possible to suppress a decrease in the accuracy of the three-dimensional measurement.

Specifically, when the pattern light PL is scanned and projected, an alternating current is usually applied to the electromagnetic coil 456, and the mirror 451 is oscillated at a certain period. Thereby, the pattern light PL is reciprocally scanned with a constant amplitude, and a fringe pattern is drawn. Then, when correcting the center position of the pattern light PL, a direct current is superimposed on the alternating current. By the superposition of the DC current, the middle value of the amplitude of the swing angle of the mirror 451 can be shifted according to the voltage value of the DC current, that is, a so-called DC offset operation can be performed. As a result, the drawing center position of the pattern light PL can be corrected, and it is possible to suppress a decrease in the accuracy of the three-dimensional measurement.

As described above, the optical scanning unit 45 as the optical scanner according to the present embodiment includes: the mirror 451; The magnet 455 is arranged on the back surface 451a of the mirror 451; the support part 452 supports the mirror 451 and has a back surface 452a (second back surface) located on the same side as the back surface 451a (first back surface); The mirror 451 is connected to the support part 452, so that the mirror 451 can swing around the swing axis J; the first part 457 is arranged on the back surface 452a (second back surface) of the support part 452; the second part 458 is connected to the swing axis J At right angles, the first member 457 is cantilevered in the direction along the back face 452a (second back face); the third member 459 is arranged opposite the first member 457 across the second member 458 and is connected to the second member 458; The electromagnetic coil 456 is arranged between the first member 457 and the third member 459 .

In such an optical scanning unit 45, the second member 458 supports the first member 457 in a cantilever direction, and the support direction thereof intersects the swing axis J. Therefore, even if the first member 457 is warped due to the generation of thermal stress, the deviation of the drawing position of the pattern light PL due to warpage can be corrected by adjusting the swing angle of the mirror 451 . Therefore, according to the optical scanning unit 45 according to the present embodiment, even if the temperature of the optical scanning unit 45 changes, the optical scanning unit 45 with high accuracy of the optical scanning position by the reflection surface 450 can be realized.

In addition, there is a certain correlation between the temperature of the optical scanning unit 45 and the amount of deviation of the position of the pattern light PL. Therefore, in the above-described DC offset operation, the voltage value of the DC voltage in the DC offset can be set based on the correlation acquired in advance so as to cancel the deviation amount estimated from the temperature of the optical scanning section 45 .

In addition, it is preferable that the optical scanning part 45 is provided with the temperature sensor which is not shown in figure. Thereby, since the temperature of the optical scanning part 45 can be detected more accurately, DC offset correction can be performed more accurately. In addition, the temperature sensor may be provided at a position in contact with the optical scanning unit 45 , or may be provided at an arbitrary position within the casing 40 . In addition, when the influence of the ambient temperature is considered, it may be provided outside the casing 40 .

In the present embodiment, when the reflection surface 450 is viewed in plan from the Z-axis direction (vertical direction), the support surface 4572 supporting the first member 457 by the second member 458 is displaced from the reflection mirror 451 and the shaft portion 453 . Moreover, in this embodiment, the support surface 4572 is also offset from the support portion 452 .

According to this configuration, the effect of the above-described cantilever support structure is more remarkable. That is, the distance between the support surface 4572 where thermal stress is easily generated and the mirror 451 can be ensured by staggering as described above. Accordingly, even if thermal stress occurs in the support surface 4572, deformation such as warpage of the first member 457 in the vicinity of the mirror 451 can be suppressed to a small extent. Further, the "staggered" means that there is no overlapping portion.

In addition, in the present embodiment, the support surface 4572 of the first member 457 supported by the second member 458 has a rectangular shape having a long axis parallel to the swing axis J as shown in FIG. 6 . Therefore, the distance between the support surface 4572 and the swing axis J is uniform. As a result, for example, even if the first member 457 is warped, the deviation of the drawing position of the pattern light PL can be corrected with higher accuracy by adjusting the swing angle of the mirror 451 .

In addition, in this specification, "parallel" means a concept that allows for variations due to manufacturing errors. The amount of deviation due to manufacturing errors is, for example, about ±5°. Likewise, in this specification, "orthogonal" refers to a concept that allows for variations due to manufacturing errors. The amount of deviation due to manufacturing errors is, for example, about ±5°.

In addition, the length X1 of the X-axis direction of the support surface 4572, that is, the length of the long axis is not particularly limited, but is preferably 5 mm or more and 30 mm or less, and more preferably 7 mm or more and 15 mm or less.

In addition, the length Y1 of the Y-axis direction of the support surface 4572 is not particularly limited, but is preferably 2 mm or more and 5 mm or less.

Furthermore, in the first member 457, when the length in the Y-axis direction of the portion not supported by the support surface 4572 is Y2 [mm], the ratio of Y2/Y1 is preferably 1.2 or more and 3.0 or less, and more preferably 1.5 or more and 2.5 or less. By setting the ratio of Y2/Y1 within the above range, the area of the mirror 451 provided in the portion not supported by the support surface 4572 can be sufficiently ensured, and the support strength of the support surface 4572 can be ensured.

Moreover, it is preferable that the length Y3 of the Y-axis direction of the support part 452 is shorter than the length Y2, and it is preferable that it is 3 mm or more and 10 mm or less as an example.

On the other hand, the length Z1 of the first member 457 in the Z-axis direction, that is, the thickness of the first member 457 is not particularly limited, but is preferably 0.2 mm or more and 2.0 mm or less, and more preferably 0.3 mm or more and 1.0 mm or less. Thereby, deformation of the first member 457 can be suppressed, and a situation in which the permanent magnet 455 and the electromagnetic coil 456 are blocked by the first member 457 and cannot be sufficiently approached can be avoided.

The length Z2 of the second member 458 in the Z-axis direction, that is, the height of the second member 458 is not particularly limited, but is preferably 2.5 mm or more and 8.0 mm or less, and more preferably 3.0 mm or more and 6.0 mm or less. Thereby, the space|interval between the 1st member 457 and the 3rd member 459 can be fully ensured, and the electromagnetic coil 456 of sufficient size can be arrange|positioned. In addition, since the heat transfer path of the second member 458 in the Z-axis direction can be ensured to be sufficiently long, the heat transferred to the third member 459 is not easily transferred to the first member 457 . As a result, the first member 457 is less likely to deform.

The thermal conductivity of the third member 459 is preferably greater than the thermal conductivity of the second member 458 . Thereby, the thermal resistance between the 3rd member 459 and the electromagnetic coil 456 arrange|positioned on the upper surface can be reduced. As a result, the heat generated by the electromagnetic coil 456 is easily transferred to the third member 459 . Accordingly, the temperature rise of the electromagnetic coil 456 can be suppressed, and the strain caused by the temperature rise of the first member 457 or the mirror 451 due to thermal radiation can be suppressed. On the other hand, since the thermal resistance between the third member 459 and the second member 458 increases, the heat transferred to the third member 459 is not easily transferred to the second member 458 . Thereby, the temperature rise of the second member 458 can be suppressed, for example, thermal stress can be suppressed from occurring at the interface between the second member 458 and the third member 459 and at the interface between the second member 458 and the first member 457 . As a result, deformation such as warpage of the first member 457 can be suppressed.

Further, the difference between the thermal conductivity of the third member 459 and the thermal conductivity of the second member 458 is preferably 10 W/m·K or more, and more preferably 20 W/m·K or more. In addition, the thermal conductivity of the third member 459 is preferably 50 W/m·K or more, and more preferably 100 W/m·K or more.

On the other hand, the thermal expansion coefficient of the first member 457 is preferably the same as the thermal expansion coefficient of the second member 458 . As a result, almost no difference in thermal expansion due to temperature change occurs between the first member 457 and the second member 458 . Therefore, thermal stress is not easily generated on the support surface 4572, and the deformation of the first member 457 can be suppressed to a particularly small value. In addition, the thermal expansion coefficient of the first member 457 is preferably the same as the thermal expansion coefficient of the support portion 452 . As a result, a difference in thermal expansion due to temperature change hardly occurs between the first member 457 and the support portion 452 . Therefore, thermal stress is less likely to be generated on the back surface 452a of the support portion 452, and the deformation of the support portion 452 can be suppressed to be particularly small. In addition, the thermal expansion coefficient of the first member 457 is preferably the same as the thermal expansion coefficient of the shaft portion 453 . Thereby, a difference in thermal expansion due to a temperature change hardly occurs between the first member 457 and the shaft portion 453 . Therefore, even if the temperature of the atmosphere around the first member 457 and the shaft portion 453 changes, the deformation of the shaft portion 453 can be suppressed to be particularly small. In addition, the thermal expansion coefficient of the first member 457 is preferably the same as the thermal expansion coefficient of the mirror 451 . As a result, almost no difference in thermal expansion due to temperature change occurs between the first member 457 and the mirror 451 . Therefore, even if the temperature of the atmosphere around the first member 457 and the reflection mirror 451 changes, the deformation of the reflection mirror 451 can be suppressed to be particularly small. In addition, the same thermal expansion coefficient means that the difference in linear expansion coefficient is 1.0×10 ⁻⁶ /K or less.

In addition, the constituent material of the first member 457 and the constituent material of the second member 458 include, for example, borosilicate glass such as Pyrex glass (registered trademark) and Tempax glass (registered trademark), and glass materials such as quartz glass, respectively. Silicon, ceramics, metals, and the like can also be cited. Among them, glass materials are preferably used. Since the thermal conductivity of the glass material is relatively small, the temperature rise of the first member 457 and the second member 458 is suppressed. Therefore, deformation of the first member 457 can be suppressed more effectively. In addition, since the linear expansion coefficient of borosilicate glass is close to that of silicon, it is preferably used when, for example, the constituent material of the support portion 452 is a silicon-based material.

On the other hand, the constituent material of the third member 459 includes, for example, metal materials such as aluminum, aluminum alloy, stainless steel, copper, copper alloy, nickel, and nickel alloy. Among them, aluminum or an aluminum alloy is preferably used. Because of their relatively high thermal conductivity, the heat generated by the electromagnetic coils 456 can be transferred more efficiently.

In addition, the first member 457 and the second member 458 are bonded or joined. Furthermore, the second member 458 and the third member 459 are also bonded or joined together. For adhesion, various adhesives such as epoxy-based adhesives, silicone-based adhesives, and acrylic-based adhesives are used. Bonding, for example, uses direct bonding.

In addition, the boundary surface of the 2nd member 458 and the 3rd member 459 is not limited to the position shown in figure. For example, the position may be shifted in the +Z-axis direction from the boundary surface shown in FIG. 7 . However, in this case, the height of the second member 458 is reduced, the thermal resistance of the second member 458 is correspondingly reduced, and the shape of the third member 459 is L-shaped when viewed from the X-axis direction, which increases the manufacturing cost. position shown in Figure 7.

As the constituent material of the support portion 452 , silicon-based materials such as silicon, silicon oxide, and silicon nitride are used, for example. Specifically, for example, the support portion 452 , the shaft portions 453 and 453 connected thereto, and the reflection mirror 451 can be formed by patterning a SOI (Silicon on Insulator, silicon on insulating substrate) substrate.

On the other hand, between the first member 457 and the support portion 452 and between the mirror 451 and the permanent magnet 455, for example, the above-mentioned adhesive or the like is used for bonding.

The three-dimensional measurement apparatus 4 shown in FIG. 1 has a casing 40 that accommodates the projection unit 41 , and the third member 459 of the optical scanning unit 45 (optical scanner) is connected to the casing 40 as shown in FIGS. 1 and 8 . For example, the third member 459 is in close contact with the housing 40 by bonding, metal bonding, screwing, or other methods. By connecting the third member 459 to the casing 40 , the heat transferred to the third member 459 can be further dissipated to the casing 40 side. Thereby, heat retention in the third member 459 can be suppressed, and heat transfer to the second member 458 can be suppressed. As a result, deformation of the first member 457 can be further suppressed.

The electromagnetic coil 456 shown in FIG. 7 includes a winding 4562 , a first magnetic core 4564 inserted inside the winding 4562 , and a second magnetic core 4566 supporting the first magnetic core 4564 . The second magnetic core 4566 has a plate shape, and is arranged on the surface of the third member 459 in the +Z axis direction. In addition, the first magnetic core 4564 has a cylindrical shape and is connected to the second magnetic core 4566 .

An alternating current and a direct current are applied to the winding 4562 from the control unit 48 through wiring not shown. In addition, the first magnetic core 4564 and the second magnetic core 4566 are cores for adjusting the magnetic circuit, respectively. By providing the first magnetic core 4564 and the second magnetic core 4566, it is possible to adjust the magnetic circuit and increase the torque for swinging the mirror 451. Therefore, the power consumption of the electromagnetic coil 456 can be reduced.

In addition, by connecting the second magnetic core 4566 to the third member 459, the heat generated by the winding 4562 is easily transferred to the third member 459 side. As a result, the temperature rise of the electromagnetic coil 456 can be further moderated.

As the constituent material of the first magnetic core 4564 and the constituent material of the second magnetic core 4566, various soft ferrite materials such as Mn-Zn-based ferrite and Ni-Zn-based ferrite can be exemplified, respectively.

As described above, the three-dimensional measurement device 4 according to the present embodiment performs three-dimensional measurement of the object W using the laser beam L, and includes the projection unit 41 and the optical scanning unit 45 for measuring the object W including the object W. An optical scanner for projecting pattern light PL formed by the laser beam L in an area; an imaging unit 47 , which acquires image data by photographing an area including the object W irradiated with the laser beam L; a control unit 48 , which controls the projection unit 41 and the imaging unit 47 is driven; and a measurement unit 49 performs three-dimensional measurement of an area including the object W based on the image data. Further, the optical scanning unit 45 includes a mirror 451 having a reflection surface 450 for reflecting light and a back surface 451a (first back surface) located on the opposite side of the reflection surface 450; a permanent magnet 455 arranged on the back surface 451a of the reflection mirror 451; a support The part 452 supports the mirror 451 and has a back surface 452a (second back surface) located on the same side as the back surface 451a (the first back surface); the shaft parts 453 and 453 connect the mirror 451 to the supporting part 452 so that the mirror 451 can be It swings around the swing axis J; the first member 457 is arranged on the back surface 452a (second back surface) of the support portion 452; the second member 458 is orthogonal to the swing axis J, in the direction along the back surface 452a (second back surface) The upper cantilever supports the first member 457; the third member 459 is arranged opposite the first member 457 across the second member 458 and is connected to the second member 458; and the electromagnetic coil 456 is arranged between the first member 457 and the third member between 459.

In the optical scanning unit 45 of the three-dimensional measuring apparatus 4 of this type, the second member 458 supports the first member 457 in a cantilever direction, and the support direction thereof intersects the swing axis J. Therefore, even if the first member 457 is warped due to thermal stress, the deviation of the drawing position of the pattern light PL caused by the warping can be corrected by adjusting the swing angle of the mirror 451 . Therefore, even if the temperature of the optical scanning section 45 changes, the optical scanning section 45 with high accuracy of the optical scanning position by the reflection surface 450 can be realized. As a result, it is possible to realize the three-dimensional measurement device 4 with high accuracy in three-dimensional measurement.

In addition, the robot system 1 according to the present embodiment includes a robot 2 including a robot arm 22 ; a three-dimensional measurement device 4 installed on the robot arm 22 to perform three-dimensional measurement of an object W using a laser beam L; and a robot control device 5 , and the driving of the robot 2 is controlled based on the measurement results of the three-dimensional measurement device 4 .

In the robot system 1 of this type, as described above, the three-dimensional measurement device 4 has high accuracy in three-dimensional measurement. Therefore, the three-dimensional information of the object W can be grasped more accurately, and the accuracy of various operations performed by the robot 2 with respect to the object W can be improved.

6. Stress Analysis

Table 1 below shows the comparison results, which are obtained by stress analysis when the temperature of the optical scanning unit 45 is changed for two models of different constituent materials of the second member 458 of the optical scanning unit 45 shown in FIG. 7 . The result of comparing the movement amount of the center of the reflection surface 450 and the inclination angle of the reflection surface 450 is the above-mentioned comparison result.

In the first model of the optical scanning portion 45, the constituent material of the mirror 451 and the constituent material of the support portion 452 are both silicon, the constituent material of the first member 457 is Tempax glass (registered trademark), and the constituent material of the second member 458 is Tempax glass (registered trademark). The constituent materials of the third member 459 are all aluminum. In the first model, the interface between the support part 452 and the first part 457 and the interface between the first part 457 and the second part 458 are bonded by adhesive, and the interface between the second part 458 and the third part 459 is formed integrally.

In the second model of the optical scanning unit 45, the second member 458 and the third member 459 are provided independently of each other, the constituent material of the second member 458 is Tempax glass (registered trademark), and the constituent material of the third member 459 is aluminum. Others are the same as the first model. In addition, in the second mold, the interface between the second member 458 and the third member 459 is bonded by an adhesive.

Regarding these two models, the behavior when the temperature is increased from 5°C to 60°C is calculated by FEM (Finite Element Method) analysis.

Table 1

The results are shown in Table 1. It can be seen that compared with the first model using aluminum, the second model using glass material as the constituent material of the second member 458 can also change the amount of center movement of the reflective surface 450 and the amount of the reflective surface 450 when the temperature changes. The inclination angles of , respectively, are suppressed to be smaller. These results show that it is preferable that the thermal conductivity of the third member 459 is greater than that of the second member 458 , the thermal expansion coefficient of the first member 457 is the same as that of the second member 458 , and the constituent material of the first member 457 and the constituent materials of the second member 458 are glass materials, respectively.

Second Embodiment

Next, the optical scanning unit 45A as the optical scanner according to the second embodiment will be described.

11 is a cross-sectional view showing an optical scanning unit 45A as an optical scanner according to the second embodiment.

Next, the second embodiment will be described. In the following description, the difference from the first embodiment will be mainly described, and the description of the same matters will be omitted. In addition, in FIG. 11, illustration of a part of a structure is abbreviate|omitted.

The optical scanning unit 45A shown in FIG. 11 is the same as the first embodiment except that the first member 457 and the second member 458 are formed integrally.

Specifically, in the optical scanning unit 45 according to the first embodiment, the first member 457 and the second member 458 are provided independently, respectively, but are integrally formed in this embodiment. According to this configuration, there is no boundary surface between the first member 457 and the second member 458 . Therefore, the adhesive stress that is easily generated at the boundary surface between the members can be eliminated, and the deformation of the first member 457 can be suppressed more reliably. As a result, the pattern light PL can be projected to a desired position, and the accuracy of the three-dimensional measurement can be improved. In addition, since the bonding process of the first member 457 and the second member 458 is unnecessary, the number of assembly steps of the optical scanning unit 45A can be reduced. The second embodiment as described above also achieves the same effects as the first embodiment.

The optical scanner, the three-dimensional measurement device, and the robot system of the present invention have been described above based on the illustrated embodiments, but the present invention is not limited thereto, and the configuration of each part may be replaced with any configuration having the same function. In addition, other arbitrary components may be added to the present invention.

In addition, the optical scanner of the present invention can also be used in applications other than three-dimensional measurement devices, and can be used in image display devices such as head-mounted displays, head-up displays, and projectors, for example.

Claims (10)

1. An optical scanner, comprising:

a mirror having a reflection surface that reflects light and a first back surface located on the opposite side of the reflection surface;

a permanent magnet disposed on the first rear surface of the mirror;

a support portion supporting the mirror and having a second back surface located on the same side as the first back surface;

a shaft portion that connects the mirror to the support portion and allows the mirror to swing about a swing shaft;

a first member disposed on the second rear surface of the support portion;

a second member orthogonal to the swing axis, the first member being cantilever-supported in a direction along the second back surface;

a third member that is disposed opposite to the first member with the second member interposed therebetween and is connected to the second member; and

an electromagnetic coil disposed between the first member and the third member.

2. The optical scanner of claim 1,

the support surface for supporting the first member by the second member is offset from the shaft portion when viewed from above in a vertical direction of the reflection surface.

3. The optical scanner according to claim 1 or 2,

the electromagnetic coil includes a magnetic core.

4. The optical scanner of claim 3,

the magnetic core is connected to the third member.

5. The optical scanner according to claim 1 or 2,

the third member has a thermal conductivity greater than a thermal conductivity of the second member.

6. The optical scanner according to claim 1 or 2,

the coefficient of thermal expansion of the first component is the same as the coefficient of thermal expansion of the second component.

7. The optical scanner of claim 6,

the first part and the second part are integral.

8. A three-dimensional measuring device is characterized in that,

the three-dimensional measurement of an object is performed using a laser beam, and the three-dimensional measurement apparatus includes:

a projection unit including an optical scanner that projects pattern light of the laser beam onto a region including the object;

an imaging unit that acquires image data by imaging a region including the object irradiated with the laser beam; and

a measurement unit that performs three-dimensional measurement of a region including the object based on the image data,

the optical scanner has:

a mirror having a reflection surface that reflects light and a first back surface located on the opposite side of the reflection surface;

a permanent magnet disposed on the first rear surface of the mirror;

a support portion supporting the mirror and having a second back surface located on the same side as the first back surface;

a shaft portion that connects the mirror to the support portion and allows the mirror to swing about a swing shaft;

a first member disposed on the second rear surface of the support portion;

a second member orthogonal to the swing axis, the first member being cantilever-supported in a direction along the second back surface;

a third member that is disposed opposite to the first member with the second member interposed therebetween and is connected to the second member; and

an electromagnetic coil disposed between the first member and the third member.

9. The three-dimensional measuring device of claim 8,

the three-dimensional measuring device has a housing for housing the projecting section,

the third component of the optical scanner is connected to the housing.

10. A robot system, characterized in that,

the robot system includes: a robot having an arm; a three-dimensional measuring device which is provided in the robot arm and performs three-dimensional measurement of an object using a laser beam; and a robot control device that controls driving of the robot based on a measurement result of the three-dimensional measurement device,

the three-dimensional measuring apparatus has:

a projection unit including an optical scanner that projects pattern light of the laser beam onto a region including the object;

an imaging unit that acquires image data by imaging a region including the object irradiated with the laser beam; and

a measurement unit that performs three-dimensional measurement of a region including the object based on the image data,

the optical scanner has:

a mirror having a reflection surface that reflects light and a first back surface located on the opposite side of the reflection surface;

a permanent magnet disposed on the first rear surface of the mirror;

a support portion supporting the mirror and having a second back surface located on the same side as the first back surface;

a shaft portion that connects the mirror to the support portion and allows the mirror to swing about a swing shaft;

a first member disposed on the second rear surface of the support portion;

a second member orthogonal to the swing axis, the first member being cantilever-supported in a direction along the second back surface;

a third member that is disposed opposite to the first member with the second member interposed therebetween and is connected to the second member; and

an electromagnetic coil disposed between the first member and the third member.

Images